Summary:
Polkowice-Sieroszowice.
In the Polkowice concession, copper mineralization covers an area 22.2 km2 at depths of 381 m to 893 m below surface. In the Sieroszowice concession, which is contiguous with Polkowice, copper mineralization extends over an area of 59.6 km2 at depths greater than 657 m below surface.
There are significant variations in the development of the Zechstein. In the western and southwestern part of the Polkowice mining area, the lowermost Zechstein is developed in the oxidized facies (Red Spotted Facies) characterized by red hematite-bearing shale and red patches and spots in the underlying White Footwall Sandstone. Copper sulphides and silver mineralization are absent, but gold and platinoids appear instead, at least at the transitional zone between the oxidized and sulphide facies. The Red Spotted Facies passes laterally (north and northeastwards) into the Cupriferous Shale, which is overlain by sulphide-bearing dolomite. The underlying White Footwall Sandstone is barren, except near the boundary with the Lubin mining area and in the northern and northwestern parts of Sieroszowice.
Structurally, the Polkowice area is divided into two domains by the Biedrzychowa Fault. This is an east-northeast striking scissor fault with a throw up to 50 m and with short northeasttrending splay faults. The area situated to the northwest and north of the fault, including the Red Spotted Facies, has a simple monoclinal structure with a gentle dip to the northeast. In contrast, the area to the southeast and east of the fault is cut by reverse south- dipping faults with vertical displacement components of 50 m to 100 m. The southern margin of the area is marked by a pre-Tertiary outcrop. Reverse faulting dies out northeastwards and, eventually, the structure assumes fairly uniform monoclinal characteristics.
There are relatively few faults in the Sieroszowice area. Those that do occur have throws ranging from 0.5 m to several metres and some are flexures rather than faults. The monoclinal structure is gently folded into west-east trending open folds. This is unique to Sieroszowice and is due to the damping effect of a salt horizon that occurs some 15 m to 25 m above the Cupriferous Shale.
Shale-carbonate ore, which predominates in Polkowice and in the developed part of Sieroszowice, generally varies from 0.6 m to 4.5 m in thickness and decreases southwards towards the pre- Tertiary outcrop. Over much of the central part of the Sieroszowice area, the thickness is reduced to 1 m to 1.5 m. Despite a relatively small variability in copper grade, the internal structure is complicated because there are low grade and barren intercalations of variable thickness. Sandstone ore appears beneath shale-carbonate ore in the southern part of the Polkowice area where it adjoins the Lubin mine and over two large areas in the undeveloped northern part of the Sieroszowice area.
Much of the relatively rich shale-carbonate ore in the central part of the Polkowice area has been exhausted and some of the rich ore still remaining, including sandstone ore, is sterilized in shaft support pillars. The richest ore in Sieroszowice (200 kg Cu/m2 to more than 350 kg Cu/m2) occurs in the developed part of the area. The richest sections of the undeveloped portion of the mining area coincide with the occurrence of sandstone underlying the carbonate-shale ore. Yields in excess of 200 kg Cu/m2 to more than 350 kg Cu/m2 are indicated by drilling in the northwestern and northeastern parts of the area, respectively. Yields of this magnitude are significantly in excess of the cut-off of 50 kg Cu/m2.
In the part of the Sieroszowice mining area, above the copper ore deposit, at a distance of 80-100 metres, a deposit of rock salt has been documented, with a thickness ranging from 40 to 150 metres, from which over 300 thousand tonnes of rock salt are extracted annually for the domestic market.
Radwanice Wschód.
Copper mineralization that was delineated by drilling from surface occurs over an area of 12.8 km2 in the central-eastern part of the documented area called Radwanice Wschód (east). This area has been accessed and mined from the Polkowice-Sieroszowice mine.
Copper mineralization above the cut-off grade is contained only in the basal part of the Zechstein. Grades in the underlying sandstone do not exceed 0.4% Cu. The depth to the footwall varies from 503 m to 691 m below surface. The thickness of the drill intersections varies from 1.1 m to 4.2 m, and averages 2.89 m. Because of the proximity to the oxidized facies, copper grades change rapidly in both horizontal and vertical directions. The highest grades are in the Cupriferous Shale (maximum 13.1% Cu). Within the resource perimeter, grades vary from 1.51% to 3.55% Cu, averaging 2.11%. Silver grades vary from 25 g/t to 45 g/t, with an average of 32 g/t.
Deep Glogów.
The Deep Glogów area covers a strip of land running from northwest to southeast, bordered to the south by the Polkowice-Sieroszowice and Rudna mines and covering an area of approximately 56 km2. The deposit will be mined from the Rudna mine (50%) and the Polkowice-Sieroszowice mine (50%), and not as a separate operation.
The copper ore deposit in the Deep Glogów area is a continuation of the deposit from the existing adjacent mining areas. The deposit has been delineated by 42 holes drilled from the surface. The depth of the deposit ranges from 1,200 m to 1,400 m below surface. The thickness of the deposit ranges from 0.74 m to 4.13 m (average 2.11 m), with a varying intensity of mineralization and a varied lithological structure.
The thinnest parts of the deposit are in the western and central region (to the north of the Polkowice-Sieroszowice mine), where the ore occurs in the Cupriferous Shale and in the roof of the White Footwall Sandstone, as well as locally in the eastern region, to the north of the Rudna mine. Three lithological types of ore have been identified: carbonate ore with an average thickness of 0.49 m (27%), shale ore with thicknesses from 0.02 m to 0.81 m (13%), and sandstone ore with thicknesses from 1.15 m to 3.59 m (60%).
The mineralization occurs mainly in the form of small grains of sulphides, most often distributed evenly, but sometimes concentrated in the form of smudges and extended pockets. Locally, coarse-grain forms of mineralization occur as veins of varying thicknesses or irregularly located pockets.
All of the ore types found in the Deep Glogów deposit are dominated by simple copper sulphides: chalcocite and digenite. The accompanying elements include lead, silver, cobalt, zinc and nickel.